trans-Di-bromido-tetra-kis-(5-methyl-1 H-pyrazole-κ N2)manganese(II)

Abstract

The title compound, trans-di-bromido-tetra-kis-(5-methyl-1H-pyrazole-κN ²)manganese(II), [MnBr₂(C₄H₆N₂)₄] or [Mn(3-MePzH)₄Br₂] (1) crystallizes in the triclinic P space group with the cell parameters a = 7.6288 (3), b = 8.7530 (4), c = 9.3794 (4) Å and α = 90.707 (4), β = 106.138 (4), γ = 114.285 (5)°, V = 542.62 (5) ų, T = 120 K. The asymmetric unit contains only half the mol-ecule with the manganese atom is situated on a crystallographic inversion center. The 3-MePzH ligands are present in an AABB type manner with two methyl groups pointing up and the other two down. The supra-molecular architecture is characterized by several inter-molecular C-H⋯N, N-H⋯Br, and C-H⋯π inter-actions. Earlier, a polymorphic structure of [Mn(3-MePzH)₄Br₂] (2) with a similar geometry and also an AABB arrangement for the pyrazole ligands was described [Reedijk et al. (1971 ▸). Inorg. Chem. 10, 2594-2599; a = 8.802 (6), b = 9.695 (5), c = 7.613 (8) Å and α = 105.12 (4), β = 114.98 (4), γ = 92.90 (3)°, V = 558.826 (5) ų, T = 295 K]. A varying supra-molecular pattern was reported, with the structure of 1 featuring a herringbone type pattern while that of structure 2 shows a pillared network type of arrangement along the a axis. A nickel complex [Ni(3-MePzH)₄Br₂] isomorphic to 1 and the analogous chloro derivatives of Fe^II, Co^II and Cu^II are also known.

Keywords: coordination compound; crystal structure; herringbone pattern; heteroleptic complex; manganese; polymorphism.

Figure 1

The mol­ecular structure of the title compound 1 with 50% probability displacement ellipsoids. The unlabeled atoms are related by symmetry.

Figure 2

Overlay of the compounds 1 and 2 showing a slight deviation of 0.0612 Å (Mercury; Macrae et al., 2020 ▸).

Figure 3

Perspective view of the supra­molecular pattern of compound 1 showing the presence of inter­molecular C—H⋯π inter­actions.

Figure 4

Supra­molecular architecture of compound 1. (a) View along the a axis showing a herringbone-type arrangement; (b) and (c) the stacking of Br—Mn—Br along the respective axes.

Figure 5

Supra­molecular architecture of compound 2. (a) View along the a axis showing a pillared network arrangement; (b) a view along the b axis showing the zigzag pattern of Br—Mn—Br and (c) a view along the c axis.